 /*******************************************************************************
  * Copyright (c) 2000, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.variables;

 import org.eclipse.core.runtime.CoreException;

 /**
  * Registry for string variables.
  * <p>
  * Clients are not intended to implement this interface.
  * </p>
  * @since 3.0
  */
 public interface IStringVariableManager {

     /**
      * Simple identifier constant (value <code>"dynamicVariables"</code>) for the
      * dynamic variables extension point.
      */
     public static final String EXTENSION_POINT_DYNAMIC_VARIABLES = "dynamicVariables"; //$NON-NLS-1$

     /**
      * Simple identifier constant (value <code>"valueVariables"</code>) for the
      * value variables extension point.
      */
     public static final String EXTENSION_POINT_VALUE_VARIABLES = "valueVariables"; //$NON-NLS-1$

     /**
      * Returns all registered variables.
      *
      * @return a collection of all registered variables
      */
     public IStringVariable[] getVariables();
     
     /**
      * Returns all registered value variables.
      *
      * @return a collection of all registered value variables
      */
     public IValueVariable[] getValueVariables();
     
     /**
      * Returns the value variable with the given name, or <code>null</code>
      * if none.
      *
      * @param name variable name
      * @return the value variable with the given name, or <code>null</code>
      * if none
      */
     public IValueVariable getValueVariable(String name);
     
     /**
      * Returns all registered dynamic variables.
      *
      * @return a collection of all registered dynamic variables
      */
     public IDynamicVariable[] getDynamicVariables();
     
     /**
      * Returns the dynamic variable with the given name or <code>null</code>
      * if none.
      *
      * @param name variable name
      * @return the dynamic variable with the given name or <code>null</code>
      * if none
      */
     public IDynamicVariable getDynamicVariable(String name);
     
     /**
      * Returns the plug-in identifier of the plug-in that contributed the
      * given variable via extension or <code>null</code> if the given
      * variable wasn't contributed via extension.
      *
      * @param variable the variable
      * @return the plug-in identifier of the plug-in that contributed the
      * given variable or <code>null</code>
      * @since 3.1
      */
     public String getContributingPluginId(IStringVariable variable);
     
     /**
      * Recursively resolves and replaces all variable references in the given
      * expression with their corresponding values. Reports errors for references
      * to undefined variables (equivalent to calling
      * <code>performStringSubstitution(expression, true)</code>).
      *
      * @param expression expression referencing variables
      * @return expression with variable references replaced with variable values
      * @throws CoreException if unable to resolve the value of one or more variables
      */
     public String performStringSubstitution(String expression) throws CoreException;
     
     /**
      * Recursively resolves and replaces all variable references in the given
      * expression with their corresponding values. Allows the client to control
      * whether references to undefined variables are reported as an error (i.e.
      * an exception is thrown).
      *
      * @param expression expression referencing variables
      * @param reportUndefinedVariables whether a reference to an undefined variable
      * is to be considered an error (i.e. throw an exception)
      * @return expression with variable references replaced with variable values
      * @throws CoreException if unable to resolve the value of one or more variables
      */
     public String performStringSubstitution(String expression, boolean reportUndefinedVariables) throws CoreException;
     
     /**
      * Validates variables references in the given expression and reports errors
      * for references to undefined variables.
      *
      * @param expression expression referencing variables
      * @throws CoreException if one or more referenced variables do not exist
      */
     public void validateStringVariables(String expression) throws CoreException;
     
     /**
      * Returns a new read-write value variable with the given name and description
      * with a <code>null</code> value.
      *
      * @param name variable name, cannot be <code>null</code>
      * @param description variable description, possibly <code>null</code>
      * @return a new value variable
      */
     public IValueVariable newValueVariable(String name, String description);

     /**
      * Returns a new value variable with the given properties.
      *
      * @param name variable name, cannot be <code>null</code>
      * @param description variable description, possibly <code>null</code>
      * @param readOnly whether this variable is to be a read only variable
      * @param value the string value to initialize this variable to - should
      * not be <code>null</code> for read-only variables
      * @return a new value variable
      * @since 3.3
      */
     public IValueVariable newValueVariable(String name, String description, boolean readOnly, String value);
     
     /**
      * Adds the given variables to the variable registry.
      *
      * @param variables the variables to add
      * @throws CoreException if one or more variables to add has a name collision with
      * an existing variable
      */
     public void addVariables(IValueVariable[] variables) throws CoreException;
     
     /**
      * Removes the given variables from the registry. Has no effect for unregistered
      * variables.
      *
      * @param variables variables to remove
      */
     public void removeVariables(IValueVariable[] variables);
     
     /**
      * Registers the given listener for value variable notifications. Has no effect
      * if an identical listener is already registered.
      *
      * @param listener value variable listener to add
      */
     public void addValueVariableListener(IValueVariableListener listener);
     
     /**
      * Removes the given listener from the list of registered value variable
      * listeners. Has no effect if an identical listener is not already registered.
      *
      * @param listener value variable listener to remove
      */
     public void removeValueVariableListener(IValueVariableListener listener);
     
     /**
      * Convenience method that returns an expression referencing the given
      * variable and optional argument. For example, calling the method with
      * a <code>varName</code> of <code>my_var</code> and an <code>argument</code>
      * of <code>my_arg</code> results in the string <code>$(my_var:my_arg}</code>.
      *
      * @param varName variable name
      * @param arg argument text or <code>null</code>
      * @return an expression referencing the given variable and
      * optional argument
      */
     public String generateVariableExpression(String varName, String arg);
     
 }

